Osceola, Iowa climate: Normal weather by month, frost dates and records
Osceola's normal year runs from 11°F January nights to 87°F July afternoons, with 38.7 inches of precipitation and 28 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.9°C, January lows of −11°C, July highs of 30°C, 984 mm of precipitation a year.
- NOAA stationOsceola
- Station IDUSC00136316
- Location41.02°N 93.75°W
- Elevation1,028 ft (313 m)
- From the center2 miles
- Population5,585
On October 23, the normal high in Osceola is 61°F and the normal low 36°F, and the chance of measurable rain or snow is 25%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Osceola.
- Jan 32° 11°
- Feb 37° 15°
- Mar 50° 26°
- Apr 62° 37°
- May 72° 49°
- Jun 82° 60°
- Jul 87° 64°
- Aug 85° 61°
- Sep 78° 51°
- Oct 65° 39°
- Nov 50° 27°
- Dec 37° 17°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Osceola each month?
July is the warmest month, with normal highs of 87°F; January the coldest, with normal lows of 11°F. The most precipitation falls in May (5.50 in), the least in January (0.97 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 32°F | 11°F | 21.8°F | 0.97 | 8.2 | 5 | <1 | 30 | 9 h 30 min |
| February | 37°F | 15°F | 25.9°F | 1.28 | 7.2 | 6 | <1 | 27 | 10 h 40 min |
| March | 50°F | 26°F | 38.2°F | 2.13 | 3.1 | 8 | <1 | 22 | 11 h 50 min |
| April | 62°F | 37°F | 49.8°F | 4.12 | 1.1 | 10 | <1 | 10 | 13 h 20 min |
| May | 72°F | 49°F | 60.7°F | 5.50 | 0.2 | 13 | 1 | 1 | 14 h 30 min |
| June | 82°F | 60°F | 70.8°F | 5.28 | 0.0 | 11 | 4 | <1 | 15 h 10 min |
| July | 87°F | 64°F | 75.2°F | 4.47 | 0.0 | 9 | 10 | <1 | 14 h 50 min |
| August | 85°F | 61°F | 73.0°F | 4.60 | 0.0 | 9 | 7 | <1 | 13 h 50 min |
| September | 78°F | 51°F | 64.7°F | 3.85 | 0.0 | 8 | 3 | 1 | 12 h 30 min |
| October | 65°F | 39°F | 52.0°F | 2.89 | 0.5 | 8 | <1 | 9 | 11 h 10 min |
| November | 50°F | 27°F | 38.5°F | 2.11 | 2.1 | 6 | <1 | 21 | 10 h |
| December | 37°F | 17°F | 27.2°F | 1.54 | 5.7 | 6 | <1 | 29 | 9 h 10 min |
| Year (annual) | 61°F | 38°F | 49.8°F | 38.74 | 28.1 | 98 | 25 | 149 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 0°C | −11°C | −5.7°C | 25 mm | 21 cm |
| February | 3°C | −9°C | −3.4°C | 33 mm | 18 cm |
| March | 10°C | −3°C | 3.4°C | 54 mm | 8 cm |
| April | 17°C | 3°C | 9.9°C | 105 mm | 3 cm |
| May | 22°C | 10°C | 15.9°C | 140 mm | 1 cm |
| June | 28°C | 15°C | 21.6°C | 134 mm | 0 cm |
| July | 30°C | 18°C | 24.0°C | 114 mm | 0 cm |
| August | 29°C | 16°C | 22.8°C | 117 mm | 0 cm |
| September | 26°C | 11°C | 18.2°C | 98 mm | 0 cm |
| October | 18°C | 4°C | 11.1°C | 73 mm | 1 cm |
| November | 10°C | −3°C | 3.6°C | 54 mm | 5 cm |
| December | 3°C | −8°C | −2.7°C | 39 mm | 14 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00136316; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Osceola?
Normal highs sit between 65°F and 85°F in May, June, August and September. Of those, September has the fewest days with rain (8).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00136316.
When is the last frost in Osceola?
In Osceola, the last spring frost (32°F) comes after April 29 in half of years and after May 11 in one year in ten; the first autumn frost comes before October 9 in half of years and before September 24 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 291 year in 10 after May 11; 9 in 10 after April 13
- First autumn frost, half of years before
- October 91 year in 10 before September 24; 9 in 10 before October 24
NOAA puts the median frost-free season at 162 days, and the season without a hard freeze (28°F) at 182 days.
A hard freeze (28°F) comes after April 18 in half of springs and before October 20 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Osceola in zone 5b in ZIP code 50213, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Osceola's NOAA station is in zone 5a: the coldest night of a typical year reaches −16°F (23 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Iowa · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00136316; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Osceola?
In a normal year in Osceola, 25 days a year reach 90°F (1 of them 100°F or more), 149 nights fall to 32°F or colder and 98 days bring measurable precipitation.
- Days at 90°F or more
- 25a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 149a normal year
- Days that stay below freezing
- 43high of 32°F or less
- Days with 0.01 inch of precipitation
- 98a normal year
- Days with 1 inch of snow or more
- 9a normal year
The highest temperature in this station's record (since 1894) is 107°F, on July 24, 1901; the lowest is −32°F, on February 9, 1899.
The wettest calendar year on that record is 1993, with 56.24 in; the snowiest season is 1961–62, with 61.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00136316; records: ACIS (NOAA Regional Climate Centers), station USC00136316. Records use complete months only; a month missing more than three days is left out.
How sunny is Osceola?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Osceola, 4.1 kWh per square metre a day. July is the sunniest month (81%) and December the cloudiest (68%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 68% | 2.0 |
| February | 74% | 3.0 |
| March | 70% | 3.8 |
| April | 69% | 4.8 |
| May | 72% | 5.7 |
| June | 77% | 6.3 |
| July | 81% | 6.4 |
| August | 80% | 5.5 |
| September | 80% | 4.6 |
| October | 73% | 3.1 |
| November | 72% | 2.2 |
| December | 68% | 1.7 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Osceola need?
A normal year in Osceola brings 6,442 heating degree days, 20% more than the median U.S. place (5,373), and 945 cooling degree days, 4% more than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,233 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,339 | 0 |
| February | 1,096 | 0 |
| March | 832 | 1 |
| April | 461 | 5 |
| May | 187 | 52 |
| June | 22 | 198 |
| July | 3 | 319 |
| August | 9 | 259 |
| September | 110 | 99 |
| October | 417 | 13 |
| November | 795 | 0 |
| December | 1,172 | 0 |
| Year (annual) | 6,442 | 945 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00136316. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Osceola been warmer than normal lately?
2024 averaged 53.4°F, 3.6°F above the 1991-2020 normal of 49.8°F. 3 of the 3 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 51.8°F | +2.0°F | 37.52 | 24.4 |
| 2022 | 49.9°F | +0.1°F | 28.77 | 32.3 |
| 2024 | 53.4°F | +3.6°F | 34.05 | 25.0 |
Over 56 complete years from 1938 to 2024, the station's annual mean temperature rose at a fitted 2.5°F per century (+0.14°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00136316; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Osceola's climate compare?
Osceola is warmer than 103 of the other 131 places with their own NOAA record in Iowa, and wetter than 108. Across the 7,247 U.S. stations with normals, its annual mean of 49.8°F is warmer than 39%.
In the Köppen classification computed from these normals, Osceola is Dfa: continental, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Osceola share this climate record?
5 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Murray, IA609 people · 10 mi W
- New Virginia, IA499 people · 11 mi N
- Van Wert, IA175 people · 11 mi S
- Weldon, IA134 people · 8 mi S
- Woodburn, IA133 people · 8 mi E
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Osceola's climate
What is the coldest month in Osceola?
January, with a normal high of 32°F and a normal low of 11°F. The warmest is July (87°F by day, 64°F at night).
Does it snow in Osceola?
Yes: 28 inches in a normal year, falling on 13 days with 0.1 inch or more, the most in January (8.2 inches).
What is the rainiest month in Osceola?
May, with 5.50 in of precipitation in a normal year; the driest is January with 0.97 in.
What plant hardiness zone is Osceola in?
The USDA's 2023 map puts Osceola in zone 5b in ZIP code 50213, the nearest ZIP area. By the same method at Osceola's NOAA station, the coldest night of a typical year reaches −16°F (23 years, 1991-2020): zone 5a.
How late can frost come in Osceola?
In half of years the last 32°F night comes after April 29; in one year in ten it comes after May 11. Waiting until May 11 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Iowa climateThe statewide normals and every place in the state
- Leon, IA21 miles from this station, 49.6°F a year
- Beaconsfield, IA21 miles from this station, 49.2°F a year
- Indianola, IA25 miles from this station, 49.9°F a year
- Chariton, IA25 miles from this station, 48.3°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made